COVID 19 PCR, SARS-CoV-2, Coronavirus
This is a qualitative PCR test for the detection of nucleic acid from patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in nasopharyngeal swabs (NPS) from individuals suspected of COVID-19 infection by their healthcare provider. Patients with COVID-19 have had mild to severe respiratory illness with symptoms of fever, cough and shortness of breath and many have had complications including pneumonia in both lungs.
Please refer to the MCHS COVID-19 Testing Algorithm (Updated 04/22/20) for COVID-19 Testing Process details. Clinicians are encouraged to use their judgment based on evolving epidemiology and guidance from CDC in combination with the above testing algorithm.
NOTE: Confirmed and suspected COVID-19 disease is a Category 1 reportable condition in Wisconsin.
Collect one (1) nasopharyngeal swab (sterile polyester tipped swab with flexible wire shaft). Place in pink M6 multi-microbe transport medium, or other acceptable transport media, cutting off or folding wire into the tube (DO NOT wrap over lip of tube). Send specimen in transport medium, and transport bio-bag. Send to lab refrigerated.
MCHS Laboratory Summary on Covid-19 Assay Sensitivity and Specificity
The current Corona virus PCR tests used at MCHS have been approved for use by regulatory authorities including the FDA and CDC. These tests are highly specific (no false-positives) and are considered to be very sensitive, approaching 100%, during symptomatic disease when high titers of viral target are present, including directly before symptoms appear and following symptom resolution for several days. Analytic sensitivity of our assays was determined to be <5 copies of viral genomic RNA per microliter of sample and the assay has been validated against a panel of specimens provided by the Wisconsin State Lab of Hygiene. Appropriate collection technique is a critical variable for best test performance.
While recent international publications have shown varying degrees of PCR assay sensitivity down to 70% or less, this occurred in high-throughput settings with early assay iterations under challenging laboratory conditions. Assays performed at MCHS use validated gene targets and reagents, strict quality control, and rigorous training by technologists. Results generated are comparable to those produced by public health and academic laboratories nationally. Unfortunately, negative test results should be viewed cautiously given unknown characteristics of viral shedding; importantly, risk levels need to be assessed prior to testing, especially for people in higher-risk groups and in areas where widespread COVID-19 infection has been confirmed.